def gen_func():

    #1. 可以产出值， 2. 可以接收值(调用方传递进来的值)

    html = yield 1

    print(html)

    yield 2

    yield 3

    return "bobby"

#1. 生成器不只可以产出值，还可以接收值

if __name__ == "__main__":

    gen = gen_func()

    #在调用send发送非none值之前，我们必须启动一次生成器， 方式有两种1. gen.send(None), 2. next(gen)

    url = gen.send(None)

    #download url

    html = "bobby"

    print(gen.send(html)) #send方法可以传递值进入生成器内部，同时还可以重启生成器执行到下一个yield位置

    print(gen.send(html))

def gen_func():

    yield "http://projectsedu.com"

    yield 2

    yield 3

    return "bobby"

if __name__ == "__main__":

    gen = gen_func()

    print(next(gen))

    gen.close()

    print(next(gen))

    print("bobby")

def gen_func():

    try:

        yield "http://projectsedu.com"

    except GeneratorExit:

        raise StopIteration

    yield 2

    yield 3

    return "bobby"

if __name__ == "__main__":

    gen = gen_func()

    print(next(gen))

    gen.close()

    print(next(gen))

    print("bobby")

def gen_func():

    #1. 可以产出值， 2. 可以接收值(调用方传递进来的值)

    try:

        yield "http://projectsedu.com"

    except Exception as e:

        pass

    try:

        yield 2

    except Exception as e:

        pass

    yield 3

    return "bobby"

if __name__ == "__main__":

    gen = gen_func()

    print(next(gen))

    gen.throw(Exception, "download error") # 实际是 yield "http://projectsedu.com" 抛出异常

　　print(next(gen))
   gen.throw(Exception, "download error1")